untitled BRITISH STANDARD BS EN 679 2005 Determination of the compressive strength of autoclaved aerated concrete The European Standard EN 679 2005 has the status of a British Standard ICS 91 100 30 �[.]
Trang 1BRITISH STANDARD BS EN
679:2005
Determination of the
compressive strength of
autoclaved aerated
concrete
The European Standard EN 679:2005 has the status of a
British Standard
ICS 91.100.30
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Trang 2BS EN 679:2005
This British Standard was
published under the authority
of the Standards Policy and
Strategy Committee
on 30 September 2005
© BSI 30 September 2005
ISBN 0 580 46612 4
National foreword
This British Standard is the official English language version of
EN 679:2005 It supersedes BS EN 679:1994 which is withdrawn
The UK participation in its preparation was entrusted to Technical Committee B/523, Prefabricated components of reinforced autoclaved aerated concrete and lightweight aggregate concrete with open structure, which has the
responsibility to:
A list of organizations represented on this committee can be obtained on request to its secretary
Cross-references
The British Standards which implement international or European
publications referred to in this document may be found in the BSI Catalogue
under the section entitled “International Standards Correspondence Index”, or
by using the “Search” facility of the BSI Electronic Catalogue or of British
Standards Online
This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application
Compliance with a British Standard does not of itself confer immunity from legal obligations.
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Summary of pages
This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 7 and a back cover
The BSI copyright notice displayed in this document indicates when the document was last issued
Amendments issued since publication
Trang 3EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
EN 679
July 2005
English version
Determination of the compressive strength of autoclaved
aerated concrete
Détermination de la résistance à la compression du béton
cellulaire autoclavé
Bestimmung der Druckfestigkeit von dampfgehärtetem
Porenbeton
This European Standard was approved by CEN on 3 June 2005
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member
This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom
EUROPEAN COMMITTEE FOR STANDARDIZATION
C O M I T É E U R O P É E N D E N O R M A L I S A T I O N
E U R O P Ä I S C H E S K O M I T E E FÜ R N O R M U N G
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved
worldwide for CEN national Members
Ref No EN 679:2005: E
Trang 4EN 679:2005 (E)
2
Foreword 3
1 Scope 4
2 Normative references 4
3 Principle 4
4 Apparatus 4
5 Test specimens 4
6 Testing procedure 6
7 Test results 7
8 Test report 7
Trang 5EN 679:2005 (E)
3
Foreword
This European Standard (EN 679:2005) has been prepared by Technical Committee CEN/TC 177
“Prefabricated reinforced components of autoclaved aerated concrete or light-weight aggregate concrete with open structure”, the secretariat of which is held by DIN
This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2006, and conflicting national standards shall be withdrawn at the latest by January 2006
This document supersedes EN 679:1993
In order to meet the performance requirements as laid down in the product standard for prefabricated components of autoclaved aerated concrete, a number of standardized test methods are necessary
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom
Trang 6EN 679:2005 (E)
4
1 Scope
This European Standard specifies the procedure for the determination of the compressive strength of autoclaved aerated concrete
The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies
EN 678, Determination of the dry density of autoclaved aerated concrete
EN 1353, Determination of moisture content of autoclaved aerated concrete
EN 12390-4, Testing hardened concrete — Part 4: Compressive strength — Specification for testing machines
3 Principle
The compressive strength is determined on test specimens as the ratio between the rupture load in axial compression and the cross-sectional area of the test specimen perpendicular to the loading direction
4 Apparatus
a) saw for cutting test specimens;
b) compression testing machine, which meets the requirements of EN 12390-4, machine class 1 or 2;
c) calipers, capable of reading the dimensions of the test specimens to an accuracy of 0,1 mm;
d) ventilated drying oven, capable of maintaining a temperature of (105 ± 5) °C;
e) straight edge, at least 200 mm long, a 0,1 mm-feeler gauge, a 1 mm-feeler gauge, and a square;
f) balance, capable of determining the mass of the test specimens to an accuracy of 0,1 %
5.1 Sample
The sample for the preparation of the test specimens shall be taken in such a manner that it is representative
of the product to be investigated
NOTE The test specimens may be prepared from prefabricated reinforced components Alternatively, they may be taken from prefabricated unreinforced components of the same mould
5.2 Shape and size of test specimens
The test specimens shall be cubes with an edge length of 100 mm Test specimens of other shapes or sizes may be used, provided that the compressive strength determined on such test specimens can be directly related to the compressive strength determined on 100 mm cubes
Trang 7EN 679:2005 (E)
5
5.3 Number of test specimens
A test set shall consist of three test specimens
Whenever possible, one test specimen shall be prepared from the upper third of the component, one from the middle and one from the lower third, in the direction of rise of the mass during manufacture (see Figure 1) The position of the test specimens in the material relative to the rise of the mass shall be shown by the numbering, and the direction of rise shall be marked on the test specimens
Key
1 Direction of rise
Figure 1— Sampling scheme 5.4 Preparation of test specimens
The test specimen shall be cut by means of a rotating carborundum blade or similar equipment They shall not contain any reinforcement All surfaces shall be plane and clean
The surfaces of the test specimen shall not deviate from planeness by more than 0,1 mm Planeness shall be checked across the two diagonal using a straight edge and a 0,1 mm-feeler gauge
The angle between the loadbearing surfaces and the adjacent surfaces shall not deviate from a right angle by more than 1 mm/100 mm This shall be checked along both orthogonal middle axes of the loadbearing surfaces by means of a square and a 1 mm-feeler gauge or similar instrument
5.5 Measurement of test specimens and determination of their volume
The dimension of the test specimen shall be measured to an accuracy of 0,1 mm, using calipers
Length and width of the loadbearing cross-sectional area, AC, shall be measured in mid height at two opposite sides, and the cross-sectional area shall be calculated by multiplying the mean values of length and width measurements
The height perpendicular to the loadbearing cross-sectional area shall be measured in the middle of two opposite sides adjacent to the loadbearing surfaces
The volume V of the test specimen shall be calculated by multiplying AC by the mean value of the height measurements
Trang 8EN 679:2005 (E)
6
5.6 Conditioning of test specimens
The test specimen shall be conditioned at a temperature not exceeding 60 °C until their moisture content is expected to be (6 ± 2) % by mass This may be estimated by comparing their moist density with the dry density determined in accordance with EN 678 on a companion specimen extracted from the same area of the same component (see NOTE)
After reaching the specified moisture content, the test specimen shall be stored, protected against moisture changes, for at least 2 h for ensuring thermal equilibrium with the laboratory at (20 ± 5) °C prior to the
compression test Immediately before the compression test the moist mass, mm, of the test specimen shall be determined again, to an accuracy of 0,1 %
NOTE The expected moisture content µm,exp., in % by mass, of a test specimen can be calculated as
100
comp
comp t m, exp
ρ
ρ ρ
where
ρm,t mm/V is the moist density of the test specimen, calculated by dividing its moist mass mm by its volume V
determined according to 5.5, in kilograms per cubic metre;
ρcomp is the dry density of the companion specimen determined according to EN 678, in kilograms per cubic metre
The platens of the testing machine shall be wiped clean, and the conditioned test specimen (see 5.6) shall be centred in the testing machine The load shall be applied axially and perpendicularly to the direction of rise The test specimen shall be loaded gradually and without shock at a constant rate corresponding to a stress increase of (0,1 ± 0,05) MPa per s until rupture of the test specimen occurs
The maximum load carried by the test specimen shall be recorded
6.2 Determination of actual moisture content and dry density of test specimens
After the compression test the test specimens shall be dried at (105 ± 5) °C until constant mass in order to determine their actual moisture content at the moment of testing in accordance with EN 1353 and their dry density in accordance with EN 678 Care shall be taken that no material is lost
If material is lost, the crushed test specimen should be weighed immediately after the compression test, and its residual volume should be calculated by multiplying its original volume V by the ratio of the moist masses determined immediately after and before the compression test
Trang 9EN 679:2005 (E)
7
The compressive strength fci, in MPa, of the test specimen i is determined as follows:
3 2
1 ,,
ci
i
ci = i=
A
F
where
Fi is the maximum load at failure, in Newton's;
Aci is the cross-sectional area to which the load is applied, determined in accordance with 5.5, in square millimetres
The compressive strength of each individual test specimen, fci, shall be expressed to the nearest 0,05 MPa
The compressive strength of the product fc, in Megapascals, is defined as the mean value of the compressive
strengths fci of the three test specimens of the test set:
3
3 2
c f f f
The compressive strength of the product, fc, shall be expressed to the nearest 0,1 Megapascal
The test report shall include the following:
a) identification of the product;
b) date of manufacture or other code;
c) place and date of testing, testing institute and person responsible for testing;
d) number and date of issue of this European Standard;
e) shape, size, and relative position of the test specimens;
f) moisture content of each individual test specimen and mean value;
g) dry density of each individual test specimen and mean value;
h) compressive strength of each individual test specimen and compressive strength of the product;
i) observations on the appearance of the test specimens
Trang 10BS EN
679:2005
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